Breastwork
in fortification, a hastily constructed parapet made of material at hand, such as earth, logs, rails, timber, and designed to protect troops from the fire of an enemy. In architecture, the parapet of a building.
In shipbuilding, a railing or balustrade standing athwartships across a deck, as on the forward end of the quarter-deck or roundhouse. The beam supporting it is a breastbeam. eck